arc: Revamp the ArcBridgeService interface

components/arc/audio/arc_audio_bridge.h

Index: components/arc/audio/arc_audio_bridge.h
diff --git a/components/arc/audio/arc_audio_bridge.h b/components/arc/audio/arc_audio_bridge.h
index 5f88b1ab10be5d4914011d52dbeece9120162749..f09b26a31d78c64ff2e37e8a6b427e96adeacdc7 100644
--- a/components/arc/audio/arc_audio_bridge.h
+++ b/components/arc/audio/arc_audio_bridge.h
@@ -15,16 +15,17 @@
 
 namespace arc {
 
-class ArcAudioBridge : public ArcService,
-                       public ArcBridgeService::Observer,
-                       public mojom::AudioHost,
-                       public chromeos::CrasAudioHandler::AudioObserver {
+class ArcAudioBridge
+    : public ArcService,
+      public ArcBridgeService::InstanceObserver<mojom::AudioInstance>,
+      public mojom::AudioHost,
+      public chromeos::CrasAudioHandler::AudioObserver {
  public:
   explicit ArcAudioBridge(ArcBridgeService* bridge_service);
   ~ArcAudioBridge() override;
 
-  // ArcBridgeService::Observer overrides.
-  void OnAudioInstanceReady() override;
+  // ArcBridgeService::InstanceObserver<mojom::AudioInstance> overrides.
+  void OnInstanceReady(mojom::AudioInstance*, uint32_t version) override;
 
   // mojom::AudioHost overrides.
   void ShowVolumeControls() override;